Tornado (web server)#Example

{{Short description|Python web server and application framework}}

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{{Infobox software

| name = Tornado

| logo = TornadoWebServerLogo.png

| screenshot =

| caption =

| author = FriendFeed

| developer = Ben Darnell, Meta, Bret Taylor

| released = {{Start date and age|2009}}

| latest release version = {{wikidata|property|reference|edit|P348}}

| latest release date = {{start date and age|{{wikidata|qualifier|P348|P577}}}}

| repo = {{URL|https://github.com/tornadoweb/tornado|Tornado Repository}}

| programming language = Python

| operating system = Cross-platform

| language = English

| genre = Web server

| license = Apache licence 2.0

}}

Tornado is a scalable, non-blocking web server and web application framework written in Python.{{cite web | url=https://github.com/tornadoweb/tornado/wiki | title=Home - tornado - GitHub | publisher=GitHub | access-date=2009-09-10}} It was developed for use by FriendFeed; the company was acquired by Facebook in 2009 and Tornado was open-sourced soon after.{{cite web | url=http://news.cnet.com/8301-17939_109-10349836-2.html | title=Facebook open-sources real-time FriendFeed facet | publisher=CNet | access-date=2009-09-10 | archive-date=2012-01-30 | archive-url=https://web.archive.org/web/20120130112658/http://news.cnet.com/8301-17939_109-10349836-2.html | url-status=dead }}

Performance

Tornado is noted for its high performance. Its design enables handling a large number of concurrent connections (i.e., tries to solve the "C10k problem").

Modules

An asynchronous MongoDB driver called Motor.
CouchDB drivers called corduroy and trombi.
Asynchronous driver for PostgreSQL wrapping psycopg called Momoko

Example

The following code shows a simple web application that displays "Hello World!" when visited:{{cite web| url=https://www.tornadoweb.org/en/stable/#hello-world |title=Hello, world |access-date=2022-09-14}}

import asyncio

import tornado.web

class MainHandler(tornado.web.RequestHandler):

def get(self):

self.write("Hello, world")

def make_app():

return tornado.web.Application([(r"/", MainHandler),])

async def main():

app = make_app()

app.listen(8888)

await asyncio.Event().wait()

if __name__ == "__main__":